Review Article

Sampling in Atypical Endometrial Hyperplasia: Which MethodResults in the Lowest Underestimation of Endometrial Cancer?A Systematic Review and Meta-analysis

Nicolas Bourdel, MD*, Pauline Chauvet, MD, Enrica Tognazza, MD, Bruno Pereira, PhD,Revaz Botchorishvili, MD, and Michel Canis, PhDFrom the Department of Gynecology Surgery, CHUEstaing Clermont-Ferrand, Clermont-Ferrand, Cedex 1, France (Drs. Bourdel, Chauvet, Botchorishvili,

and Canis), Hopital Mirano, Mirano, Italy (Dr. Tognazza), and Biostatistics Unit, University Hospital Cermont-Ferrand, Clermont-Ferrand, Cedex, France

(Dr. Pereira).

ABSTRACT Our objective was to identify the most accurate method of endometrial sampling for the diagnosis of complex atypical hyper-

The authors decla

Corresponding au

Surgery, CHU

Cedex 1, France

E-mail: nicolas.b

Submitted Januar

Available at www

1553-4650/$ - see

http://dx.doi.org/1

plasia (CAH), and the related risk of underestimation of endometrial cancer. We conducted a systematic literature search inPubMed and EMBASE (January 1999–September 2013) to identify all registered articles on this subject. Studies wereselected with a 2-step method. First, titles and abstracts were analyzed by 2 reviewers, and 69 relevant articles were selectedfor full reading. Then, the full articles were evaluated to determine whether full inclusion criteria were met. We selected 27studies, taking into consideration the comparison between histology of endometrial hyperplasia obtained by diagnostic tests ofinterest (uterine curettage, hysteroscopically guided biopsy, or hysteroscopic endometrial resection) and subsequent results ofhysterectomy. Analysis of the studies reviewed focused on 1106 patients with a preoperative diagnosis of atypical endometrialhyperplasia. Themean risk of finding endometrial cancer at hysterectomy after atypical endometrial hyperplasia diagnosed byuterine curettage was 32.7% (95% confidence interval [CI], 26.2–39.9), with a risk of 45.3% (95% CI, 32.8–58.5) afterhysteroscopically guided biopsy and 5.8% (95% CI, 0.8–31.7) after hysteroscopic resection. In total, the risk of underestima-tion of endometrial cancer reaches a very high rate in patients with CAH using the classic method of evaluation (i.e., uterinecurettage or hysteroscopically guided biopsy). This rate of underdiagnosed endometrial cancer leads to the risk of inappro-priate surgical procedures (31.7% of tubal conservation in the data available and no abdominal exploration in 24.6% of thecases). Hysteroscopic resection seems to reduce the risk of underdiagnosed endometrial cancer. Journal of Minimally InvasiveGynecology (2016) 23, 692–701 � 2016 AAGL. All rights reserved.

Keywords: Endometrial cancer; Endometrial sampling; Hysteroscopy

Endometrial hyperplasia is usually detected after investi-gation of perimenopausal women with abnormal uterinebleeding. It is defined as an excessive proliferation of glandsof irregular size and shape with an increase in the glands/stroma ratio [1].

As shown in previous studies, these lesions may coexistwith endometrial cancer (EC) at the time of diagnosis in43% to 50% of cases [2,3]; however, they may also

re that they have no conflict of interest.

thor: Nicolas Bourdel, MD, Department of Gynecologic

Estaing Clermont-Ferrand, 63058 Clermont-Ferrand,

.

ourdel@gmail.com

y 14, 2016. Accepted for publication March 22, 2016.

.sciencedirect.com and www.jmig.org

front matter � 2016 AAGL. All rights reserved.

0.1016/j.jmig.2016.03.017

progress to it. The risk of endometrial hyperplasiaprogressing to carcinoma is related to the presence andseverity of cytologic atypia [4]. It has been shown that pro-gression to carcinoma occurs in 1% of patients with simplehyperplasia, 3% of patients with complex hyperplasia, 8% ofpatients with atypical simple hyperplasia, and 29% ofpatients with atypical complex hyperplasia [5]. Failure toevaluate precisely patients with endometrial hyperplasiacan result in undertreatment; although endometrial hyper-plasia can be treated successfully with progestins or medicaltherapy, hysterectomy is recommended for postmenopausalwomen with cytologic atypia [1].

It is not yet known which is the most accurate method toobtain histologic samples; for many years, dilatation andcurettage (D&C) has been the method of choice for diag-nosing endometrial pathology in women with abnormal

Bourdel et al. Sampling in Atypical Endometrial Hyperplasia 693

uterine bleeding. However, in 60% of the curettage proce-dures, less than half of the uterine cavity is curetted, therebycalling the accuracy of this method into question [6]. More-over, the whole or parts of the focal lesion may remain in theuterine cavity after D&C in 87% of women with focallygrowing lesions [7].

Some authors stress the high accuracy of hysteroscopy fordistinguishing between a normal and an abnormal endome-trium thanks to the advantages of high magnification fordirect visualization of the uterine cavity and the possibilitiesof targeted biopsies [8].

Methods

This review was conducted in order to understand the riskof coexisting EC in patients with a diagnosis of complexatypical hyperplasia (CAH) by endometrial biopsy, takinginto account the method used to do this (i.e., direct biopsyduring hysteroscopy, endometrial hysteroscopic resection,or D&C of the uterine cavity). We decided to not considerdifferent forms of atypical endometrial hyperplasia (simpleand complex hyperplasia) because those data were missingin most articles, and, furthermore, the histologic diagnosisis difficult and controversial.

Studies about Pipelle were not included in our reviewbecause we decided to focus on the 3 sampling methodsthat seemed the most reliable to us [9,10]. Furthermore,there is a minority of studies comparing Pipelle and a realgold standard such as hysterectomy. The majority ofstudies included only patients who had undergone D&C asthe reference. Even if this method is probably the mostcommon method of endometrial sampling for abnormaluterine bleeding or postmenopausal bleeding, office biopsymay be insufficient to detect endometrial disease becauseblind techniques of sampling are not indicated for focalanomalies. The nonrepresentative nature of these blindprocedures may be related to the small proportion of theendometrial surface sampled [10].

Literature Search

A computerized search in PubMed and EMBASE wasperformed to identify all registered articles on this subjectpublished between January 1999 and September 2013restricted to English, French, Italian, or Spanish languages.We used the following subsets of search terms combinedby the word ‘‘and’’: ‘‘hysteroscopy,’’ ‘‘curettage,’’ ‘‘endome-trial resection,’’ ‘‘endometrial hyperplasia,’’ ‘‘endometrialcancer,’’ and ‘‘hysterectomy.’’ In addition, cross-referencesof all selected articles were checked.

Study Selection

The review focused on studies (clinical trials, compara-tive studies, controlled clinical trials, randomized controlledtrials, and multicenter studies) in which the results of the

diagnostic test of interest were compared with the resultsof a reference standard.

The population of interest was premenopausal and post-menopausal women submitted to endometrial samplingbecause of a suspicion of endometrial disease (with orwithout symptoms) with a diagnosis of atypical endometrialhyperplasia and who underwent hysterectomy. We excludedpopulations consisting entirely of patients treated by tamox-ifen or affected by familiar diseases (i.e., HNPCC [Heredi-tary Non-Polyposis Colorectal Cancer] syndrome) becauseof the different prevalence of EC in this population influ-encing outcome measures. We also excluded studies inwhich the histologic findings were not compared with thereference standard (i.e., hysterectomy), the samplingmethods were different from the 3 diagnostic tests, and hys-terectomy was realized for other indications.

The diagnostic tests were uterine curettage (group 1),hysteroscopically guided biopsy (group 2), and endometrialhysteroscopic resection (group 3), and the reference stan-dard was hysterectomy. The primary outcome measurewas the percentage of unexpected cancer cases diagnosedat hysterectomy and missed during endometrial sampling(endometrial sampling with histologic diagnosis of atypicalendometrial hyperplasia).

In some studies, other techniques of endometrial sam-pling (i.e., Pipelle, Vabra, or others) were performed alongwith curettage, hysteroscopically guided biopsy, or hystero-scopic endometrial resection. In these cases, we includedonly the population submitted to the reference test.

When the histopathology results were described very pre-cisely, data were recorded in ‘‘simplified’’ histologic groupsincluding ‘‘atypical endometrial hyperplasia,’’ ‘‘nonatypicalendometrial hyperplasia,’’ and ‘‘others’’ (including polyps,atrophic endometrium, and proliferative or secretory endo-metrium).

Finally, for each study and for all of them, the percentage ofendometrial sampling results that failed to detect the correctdiagnosis of EC was calculated. The surgical procedureto perform the hysterectomy was recorded when specified.

The search resulted in 1938 PubMed abstracts (Fig. 1); 2reviewers read those abstracts and titles, and, of these, 69relevant articles were selected for full reading. The full arti-cles of these examples were then evaluated by 2 reviewers todetermine whether full inclusion criteria were met.

In total, 42 studies were excluded because of variousreasons including reference standard different from hyster-ectomy [7,11–15], use of hysteroscopy without biopsy[16] or endometrial biopsy without previous hysteroscopy[17–20], use of curetting methods different from thestandard (i.e., D&C) [21,22], inclusion of patientssubmitted to hysterectomy for a diagnosis other thanendometrial hyperplasia (i.e., EC and carcinoma in situ)[23–27], correlation between specific histology group andhysterectomy not available [28–31], more complete data ina subsequent article [32], and use of several sampling testswithout taking them separately [33,34].

Fig. 1

A flow diagram of the study selection process.

694 Journal of Minimally Invasive Gynecology, Vol 23, No 5, July/August 2016

A total of 27 studies were finally included in our review,with agreement of the 2 reviewers. For each study, the 2reviewers recorded the sampling technique, the histologicresult of endometrial sampling, and the number of ECs diag-nosed at hysterectomy. We also analyzed the characteristicsof the population (premenopausal or postmenopausal, themean population age with standard deviation, and rangewhen present). The data were recorded in an electronic data-base.

A total of 1106 patients with a preoperative diagnosis ofatypical endometrial hyperplasia were included in ourreview. Twenty-two of the 27 studies compared uterinecurettage with hysterectomy [35–47], 6 comparedhistology obtained by hysteroscopically guided biopsywith hysterectomy [45,48–52], and 3 studies comparedhistology obtained by endometrial hysteroscopic resectionwith hysterectomy [45,48,53]. Characteristics of studiesare summarized in Table 1. Most of the studies includedpre- and postmenopausal subjects. Two studies had a post-menopausal population only [12,39], and 5 articles did notspecify menopausal status [38,42,47,51,54].

Fifteen studies included patients given hysterectomybased exclusively on a previous diagnosis of atypical hyper-plasia [35,38,41–43,45,48,50–57]. The remaining studiesdistinguished among different histologic diagnoses

(such as simple hyperplasia with and without atypia,complex hyperplasia with and without atypia,endometrial polyps, and dysfunctional endometrium)[36,37,39,40,44,46,47,49,58–61]. In this category, most ofthe time surgical indications included abnormaluterine bleeding [36,37,39,40,44,47,49,58–61], butleiomyoma [46,49], endometriosis [46], adenomyosis [61],cervical polyps, and abnormal endometrial thickness inmenopause [49] were also included.

Three studies considered repeated tests on the samepatients, performing a ‘‘multistep’’ preoperative diagnosis.In these studies, we considered only the results obtainedby the diagnostic test of interest.

Statistical Analysis

Comprehensive meta-analysis software [62] was usedto conduct random-effects meta-analyses. Heterogeneityin the study results was evaluated by examining forestplots and confidence intervals and by using formal testsfor homogeneity based on the I2 statistics. A forest plotgraph is presented in Figure 2. Heterogeneity was quan-tified by I2 [63]. Publication bias was assessed by a fun-nel plot (Fig. 3); in this figure, each dot representsa study, and each symbol represents a group. Thus,

Table 1

Characteristics of the studies

Author Population

Total no. of

patients in

the study

No. of

patients

submitted

to tests

of interest

Type of test

of interest Symptoms

Mean age 6 SD

(range)

Canadian

Task

Force

Whyte et al, 2010 Pre- and postmenopausal 88 51 D&C NS 53.9 (37–85) II-2

Chen et al, 2009 Pre- and postmenopausal 77 77 D&C AUB 49.6 II-2

Obeidat et al, 2009 Pre- and postmenopausal 55 55 D&C NS 51.8 (35–74) II-2

Suh-Burgmann

et al, 2009

NS 824 193 D&C NS 56 (27–85) II-2

Edris et al, 2007 Pre- and postmenopausal 22 4 HSC-res AUB 55.5 (46–78) II-3

Garuti et al, 2006 Post-menopausal 28 25 HSC-bio AUB/increased

endometrial

thickness

61 6 6.1 II-3

Saygili et al,

2006 NS

Post-menopausal 42 42 D&C AUB/increased

endometrial

thickness

NS II-3

Karamursel et al,

2005

Pre- and postmenopausal 204 204 D&C AUB 57.4 6 9.3 (28–87) II-2

Merisio et al, 2005 Pre- and postmenopausal 70 39 D&C NS 55.51 6 11.9 (38–30) II-3

Shutter et al, 2005 NS 60 30 D&C NS NS II-3

Bilgin et al, 2004 Pre- and postmenopausal 46 38 D&C NS 48.9 6 8.3 II-2

Agostini et al, 2003 Pre- and postmenopausal 25 23 HSC-bio/

HSCres

AUB 53.4 (45–76) II-3

Gundem et al, 2003 Pre- and postmenopausal 103 103 D&C AUB 48.7 6 6.9 (36–78) II-2

Valenzuela

et al, 2003

Pre- and postmenopausal 23 20 D&C/HSCbio/

HSC-res

NS 52 (30–83) II-3

Ceci et al, 2002 Pre- and postmenopausal 443 443 HSC-bio AUB/increased

endometrial

thickness

52 II-2

Xie et al, 2002 Pre- and postmenopausal 150 150 D&C NS 48.5 (31–76) II-2

Bettocchi et al,

2001

NS 397 397 D&C AUB/endometrial

polyp

43 II-2

Hahn et al, 2010 NS 141 126 D&C,

HSC-bio

AUB 45.4 (25–65) II-2

Leitao Jr. et al,

2010

Pre- and postmenopausal 197 123 D&C NS 54 (32–86) II-2

Yarandi et al, 2010 Pre- and postmenopausal 311 311 D&C AUB 46.6 (30–86) II-2

Daud et al, 2011 Pre- and postmenopausal 280 220 D&C AUB 55.7 6 11.4 II-2

Kurosawa et al,

2012

Pre- and postmenopausal 22 22 HSC-bio NS 53.4 II-2

Demirkiran et al,

2012

Pre- and postmenopausal 673 161 D&C AUB/increased

endometrial

thickness

45.3 (27–86) II-2

Barut et al, 2012 Pre- and postmenopausal 645 645 D&C NS 50.9 (23–81) II-2

Saleh et al, 2012 Pre- and postmenopausal 137 93 D&C AUB 49.1 (35–76) II-2

Kurt et al, 2011 Pre- and postmenopausal 58 58 D&C AUB 51.7 6 9.2 II-3

Robbe et al, 2012 NS 39 29 D&C NS 60.4 (34–90) II-3

AUB5 abnormal uterine bleeding; D&C5 dilatation and curettage; HSC-bio5 hysteroscopically guided biopsy; HSC-res5 endometrial hysteroscopic resection; NS5 not

specified; SD 5 standard deviation.

Bourdel et al. Sampling in Atypical Endometrial Hyperplasia 695

a sensitivity analysis was conducted to assess the influ-ence on the global effect size of the inclusion and exclu-sion of some studies.

For appraisal of the methodologic quality of thestudies, we used the Canadian Task Force classification,a measurement tool to assess the methodologic quality

Fig. 2

A forest plot graph.

696 Journal of Minimally Invasive Gynecology, Vol 23, No 5, July/August 2016

of studies (Table 1). Most of the studies included wereclassified II-2 (n 5 19/27) (i.e., evidence obtained fromwell-designed cohort or case-control studies), and 8

Fig. 3

A funnel plot.

were classified II-3 (i.e., evidence obtained from severaltimed series with or without the intervention). All studiesincluded were retrospective, and subjects were alwaysincluded when they had a preoperative diagnosis of atyp-ical endometrial hyperplasia followed by hysterectomywith pathological analysis.

Table 2

Main results

Group Risk of undiagnosed endometrial cancer

I: D&C 32.7% (CI 95% [26.2–39.9])

II: HSC-bio 45.3% (CI 95% [32.8–58.5])

III: HSC-res 5.8% (CI 95% [0.8–31.7])

CI 5 confidence interval; D&C 5 dilatation and curettage; HSC-

bio 5 hysteroscopically guided biopsy; HSC-res 5 endometrial hysterscopic

resection.

Global omnibus p value: p 5 .043.

Bourdel et al. Sampling in Atypical Endometrial Hyperplasia 697

Results

The total number of patients with a preoperative diag-nosis of atypical endometrial hyperplasia based on curettage(group 1) was 984; of these 984 cases, 296 were diagnosed tohave EC at hysterectomy (30.1%), varying from 0% to66.6%. Using the random-effects model, the risk of havingundiagnosed EC after D&C for atypical endometrial hyper-plasia was 32.7% (95% confidence interval [CI], 26.2–39.9).

The total number of patients with a preoperativediagnosis of atypical endometrial hyperplasia based onhysteroscopically guided biopsy (group 2) was 99. EC wasdiagnosed at hysterectomy in 46 patients (46.5%), and theresult using the random-effects model was 45.3%(95% CI, 32.8–58.5).

The number of patients submitted to endometrial resec-tion with a diagnosis of atypical endometrial hyperplasia(group 3) was 23; of these 23, only 1 had EC at hysterectomy(4.3%), resulting in 5.8% (95% CI, 0.8–31.7) with therandom-effects model.

Between the 3 techniques, there was a significantdifference (global p value 5 .043). This difference stayedsignificant between groups 3 and 2 (p 5 .03) but becamenonsignificant between the other groups (p 5 .06 andp5 .21) because of the heterogeneity of the groups. Howev-er, there was a significant trend between endometrialresection and the 2 other groups (Table 2).

Only 8 articles specified the surgical approach, including369 hysterectomies. Of these, 231 were abdominal hysterec-tomies (134 with bilateral salpingo-oophorectomy [BSO][36.3%] and 97 without BSO [26.3%]), 91 were vaginalhysterectomies (71 with BSO [19.2%] and 20 withoutBSO [5.4%]), 7 were laparoscopic assisted with BSO(1.9%), and 40 were laparoscopic hysterectomies withBSO (10.8%) [35,41,45,50,52,53,56]. In total, 117hysterectomies were realized without BSO (31.7%) and 91without abdominal exploration (24.6%). Of thehysterectomies performed without BSO or abdominalexploration, the number of ECs was not specified at thetime of the intraoperative assessment.

Discussion

The most accurate and reliable method of endometrialsampling when endometrial disease is suspected is not yetestablished, so several methods of endometrial samplingare commonly used. If the most accurate procedure wereknown, the incidence of missed ECs would be reducedsignificantly, resulting in optimal clinical management ofpatients diagnosed with endometrial hyperplasia.

Main Findings

In our study, we performed the first meta-analysis to investi-gate the correlation of hysteroscopically guided biopsy, hyster-oscopic endometrial resection, and uterine curettage tothe presence of EC on hysterectomy. In our study, the risk of

underestimation of EC seemed to be higher when a diagnosisof atypical endometrial hyperplasia was made with uterinecurettage and hysteroscopically guided biopsy compared withresection. These results need to be confirmed by larger studies.

Comparison Between Hysteroscopic Techniques ofEndometrial Sampling and Uterine Curettage

The literature is lacking in studies focused on the compar-ison between hysteroscopy and curettage for the diagnosis ofatypical endometrial hyperplasia, whereas a number ofstudies compare other sampling methods (mainly D&Cand Pipelle). Three studies were found comparing D&Cwith hysteroscopically guided biopsy in perimenopausalwomen [49,51,64]. In the first, the authors found thathysteroscopy with directed biopsy was more effective thanD&C for collecting endometrial samples adequate forhistologic examination in all types of uterine lesions [64](N 5 734). In the second, hysteroscopy demonstrated agreater diagnostic accuracy than D&C, showing a statisti-cally significant difference in the sensitivity and the negativepredictive value for benign and malignant endometrialpathologies [49] (N 5 443). Conversely, in the third study[51], the results indicated a greater reliability of D&Ccompared with hysteroscopically guided biopsy for the num-ber of cases of underdiagnosed EC (N 5 126).

Complications of sampling procedures were not reportedor discussed in any of the articles. However, we know thathysteroscopic resectionmay have a higher incidence of com-plications (e.g., fluid overload). Furthermore, hysteroscopicresection is a more invasive procedure, and there is a reallearning curve for improvement in performing hysteroscopicresection.

The techniques are slightly different; most of the timehysteroscopic resection requires patient hospitalization andanesthetic study and, during the procedure, dilatation ofthe cervix and use of distension medium. Conversely, directendometrial biopsy can be performed by hysteroscopy in anoutpatient office setting with less exposure time. Further-more, a pathological study is shorter because the amountof endometrial tissue to analyze is smaller. All this shortensthe time to definitive intervention with less cost. However, inour study, we did not focus on financial differences betweenthose different sampling methods.

Role of Office Biopsy in the Detection of EndometrialHyperplasia

The literature is rich in studies about the efficacy of blindbiopsy (‘‘office biopsy’’) in diagnosing endometrial disease(cancer and hyperplasia). One meta-analysis including 7914pre- and postmenopausal women compared endometrialbiopsies obtained by different devices (Pipelle, Vabra, Novak,and others) with histologic findings obtained by D&C, hyster-ectomy, or both. The results showed that endometrial biopsywith Pipelle is better than other endometrial techniques

698 Journal of Minimally Invasive Gynecology, Vol 23, No 5, July/August 2016

(Vabra, Novak, and others) in the detection of EC and atypicalhyperplasia [20] (detection rate of 99.6% in postmenopausalwomen and 91% in premenopausal women). In this study,only a minority of the studies included patients who had atrue gold standard (hysterectomy) (n5 2130, 26.9%), whereasthe majority of studies included only patients who had under-gone D&C as the reference (n 5 3622, 45.8%). The othersstudies included patients who underwent hysterectomy, D&C,or hysteroscopy without distinction. In recent years, severalpublications have reported that the accuracy of D&C is limitedbecause in 60% of the curettage procedures less than half of theuterine cavity is curetted [8]. In this meta-analysis, they did notperform a separate analysis for studies that used either hysterec-tomy or D&C as the reference. Those results of detection ofendometrial carcinoma and atypical hyperplasia with Pipelleare not suitable because D&C should not be used as a referencebecause of the high risk of underdiagnosed endometrial carci-noma. (In our study, the risk of having undiagnosed EC afterD&C for atypical endometrial hyperplasia was 32.7%).

Furthermore, office biopsy may be insufficient to detectendometrial disease because blind techniques of samplingare not indicated for focal anomalies. The nonrepresentativenature of these blind procedures may be related to the smallproportion of the endometrial surface sampled [65].

This observation was confirmed by the review conductedby Clark et al in 2001 [19]. Studies were selected if the ac-curacy of outpatient endometrial biopsy, in women withabnormal pre- or postmenopausal uterine bleeding, was esti-mated compared with a reference standard, which was endo-metrial histology obtained by tissue sampling underanesthesia. The review included 881 women. The resultsshow that endometrial biopsy alone has modest overall accu-racy in diagnosing endometrial hyperplasia and is onlymoderately useful in informing clinical decision making.Therefore, additional endometrial assessment with outpa-tient hysteroscopy and/or transvaginal ultrasonographyshould be undertaken.

Similarly, transvaginal ultrasonography could be impor-tant and should be evaluated. In our work, 2 studies[52,60] evaluated the interest of ultrasound, measuringendometrial thickness. It is known that most endometrialpathologies are associated with a thickened endometrium.In the first study [52], ultrasound was performed after endo-metrial sampling and before surgery. No significant differ-ence was found between patients with CAH and those witha final diagnosis of endometrial carcinoma at hysterectomy.In the second study [60], no statistically significant effect ofendometrial thickness was shown on biopsy results becauseit allows a large number of cases of abnormal uterinebleeding to be diagnosed (e.g., polyps).

Role of Operative Hysteroscopy in the Diagnosis ofEndometrial Hyperplasia

Hysteroscopic endometrial resection has a particularplace among other techniques of endometrial sampling.

The total number of patients included in group 3 was small(n 5 23). Out of 3 studies, only 4 and 2 cases [45,53] wereincluded in 2 studies, with no cancer diagnosed insubsequent hysterectomy. The percentage of unexpectedcancer after hysteroscopic resection (group 3) seems to belower than observed in other groups (groups 1 and 2), evenif it is only a significant trend, and this could be related tothe technique itself. In fact, in hysteroscopic resection,most of the endometrium is removed, unlike the other 2techniques when only endometrial sampling is performed.There are no specific hysteroscopic signs of malignancy,and between groups 2 and 3, the benefit of resection couldbe caused only by the completeness of the sample.

In total, according to our results, hysteroscopic resectionseems to be a complete and reliable analysis, but these hy-potheses need to be confirmed by other studies, especiallybecause these results were obtained with a small numberof patients. Hysteroscopic resection seems to be a safemethod of endometrial sampling, albeit more expensive,but the initial investment is probably justified in terms ofimproved screening and therefore profits over the long-term.

Complexity of Histologic Diagnosis of AtypicalEndometrial Hyperplasia

Only 1 article considered different forms of atypicalendometrial hyperplasia [51]; of the 126 patients who under-went hysterectomy for preoperative diagnosis of CAH, 24patients were diagnosed with simple CAH (19%) and 102patients (81%) with complex CAH. There were no patientswith endometrial carcinoma after hysterectomy among thepatients who carried a preoperative diagnosis of simpleCAH. The high rate of misdiagnosed cancer among patientsdiagnosed with CAH may be related in part to the fact thatthis diagnosis is often controversial and difficult to make,even for expert pathologists. The rate of agreement among3 expert pathologists on 306 endometrial samples identifiedas CAH was 38%, whereas they suggested in 29% of cases amore severe diagnosis and in 25% a less severe diagnosis[65]. In another study, the mean percentage of agreementwas lowest for complex hyperplasia and for atypical hyper-plasia in the diagnosis of 56 endometrial specimens by 5 Eu-ropean expert gynecologic pathologists using the WorldHealth Organization classification. The authors suggestedthat the lack of agreement and reproducibility in the recog-nition of the histologic feature of stromal alterations todifferentiate atypical hyperplasia from well-differentiatedadenocarcinoma involves an evolution in the histologicclassification. This should be simplified by including a com-bined category for simple and complex hyperplasia calledhyperplasia and a combined category for atypical hyperpla-sia and well-differentiated adenocarcinoma called endome-trioid hyperplasia [66]. In our study, we decided not toconsider different forms of atypical endometrial hyperplasiabecause of that complexity of histologic diagnosis. Further-more, data were missing in most articles.

Bourdel et al. Sampling in Atypical Endometrial Hyperplasia 699

It should be noted that there is a new nomenclature thatnow refers to atypical endometrial hyperplasia as ‘‘endome-trial intraepithelial neoplasia.’’ In our study, we decided notto use this new nomenclature because in the studies includedthe endometrial pathology is called atypical endometrialhyperplasia.

Surgical Management of Patients With AtypicalEndometrial Hyperplasia

Knowledge of the risk of underestimating EC is importantfor subsequent clinical management. A cancer diagnosisshould lead to preoperative staging (i.e., magnetic resonanceimaging), which should be performed to exclude overt my-ometrial invasion and cervical or adnexal involvement.Expert ultrasound can be considered as an alternative (levelof evidence: III, strength of recommendation: B) [67,68].This can also lead to a different surgical approach(laparotomy or laparoscopy route) and procedure (BSO,abdominal exploration, lymph node dissection, etc.); aspecialized gynecologic oncologist should performsurgery if it is cancer. During hysterectomy for CAH,intraoperative frozen section may be performed todetermine the presence of EC and the depth of tumorinvasion. Nevertheless, some authors suggest poorreliability of this test for the detection of invasive disease[69], reconsidering comprehensive surgical staging afterthe diagnosis of CAH like in EC [35]. In a recent multicenterprospective cohort study (Gynecologic Oncology Group no.167), Trimble et al [30] reported that 42.6% (123/289) ofwomen undergoing hysterectomy for definitive managementof CAH had endometrial carcinoma in their hysterectomyspecimens and that although the great majority of the tumorswere grade 1, 6 tumors were grade 2, and 2 tumors weregrade 3. Of the carcinomas identified, 105 of 123 tumors(85.4%) were stage IA considering F�ed�eration Internationalede Gyn�ecologie et d’Obst�etrique classification 2009; 13(10.6%) were IB (myoinvasive involved the outer 50% ofthe myometrium). For 5 tumors, there was no stage classifi-cation [30].

In the presence of myometrial infiltration, the risk oflymph node infiltration exists, and lymphadenectomy shouldbe discussed [35]. In our study, only 8 articles specified thesurgical approach. Of the 369 hysterectomies, 117 were per-formed without BSO (97 abdominal hysterectomies and 20vaginal hysterectomies). All the laparoscopic-assisted orlaparoscopic hysterectomies were performed with BSO.With the rate of underestimated EC after D&C or hystero-scopically guided biopsy, the surgical procedure shouldsystematically respect oncologic rules. During hysterec-tomy, BSO and abdominal evaluation should at least be dis-cussed. The fact that 117 hysterectomies were performedwithout BSO (31.7%) and 91 without abdominal exploration(24.6%) is questionable with respect to the oncologic rules(10.6% of undiagnosed cancers were finally stage IB [30]).Despite this, at the moment, laparoscopy seems to be the

less used surgical method to perform hysterectomy withBSO in patients with CAH.

Finally, the safety of hysteroscopy in cases of EC shouldbe discussed. A recent meta-analysis, including 9 trials for atotal of 1015 patients, suggested that diagnostic hysterosco-py in women with EC results in statistically significanthigher endometrial cell seeding in the peritoneal cavityand statistically significant higher tumor upstaging in pa-tients with disease limited to the uterus compared with nohysteroscopy (D&C, biopsy, or no diagnostic test beforehysterectomy) [68]. The degree of tumor cell disseminationis increased by isotonic sodium chloride as the distensionmedium and when high levels of inflated media pressureare reached (100 mm Hg). Nevertheless, the prognostic sig-nificance of positive peritoneal cytology after diagnostichysteroscopy is unclear. Furthermore, in their study, Ben-Arie et al [70] compared the outcome measures of patients(N 5 392) with endometrial adenocarcinoma diagnosed byendometrial biopsy, uterine curettage, or hysteroscopy.They showed no statistically significant difference in the sur-vival rate or recurrence rate between the different diagnosticmethods applied [70]. Consequently, hysteroscopy can besafely used in case of EC suspicion.

Globally, with the risk of underestimated EC, the surgicalprocedure should systematically respect oncologic rules, soBSO and an abdominal evaluation should be associated dur-ing the same surgical procedure.

Strengths and Weaknesses of the Review

The methodologic quality of the included studies wasanalyzed using the Canadian Task Force classification,with most of the studies assessed as not being of high quality.

A limitation of this review is the heterogeneity of popula-tions and groups, which may impact the generalizability ofthe findings. There are 22 studies (n5 984 patients) in group1, 6 in group 2 (n5 99), and only 3 in group 3 (n5 23). Thisdifference causes a high heterogeneity (total I2 5 67.8 withI25 72.0 for group 1, I25 30.6 for group 2, and I25 0.0 forgroup 3). However, we used a random-effects analysis totake account of this heterogeneity, and the results indicateda statistically significant difference.

Conclusion

A review of the literature shows that hysteroscopicallyguided biopsy and uterine curettage may have a high riskof underestimation of EC, and this rate of underdiagnosedEC could lead to inappropriate surgical procedures. Hyster-oscopic endometrial resection seems to lower this risk. How-ever, this review highlights the need for a larger amount ofdata to confirm this observation, and the standard approachfor evaluation of the uterine cavity could change in favorof operative hysteroscopic techniques, especially in casesof women at risk of serious endometrial disease.

700 Journal of Minimally Invasive Gynecology, Vol 23, No 5, July/August 2016

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